This invention relates generally to inflatable passive restraint systems for use in vehicles for restraining the movement of a seated occupant during a collision and, more particularly, to air bag modules units and the attachment of air bag module doors therein.
The value of safety restraint systems which self-actuate from an undeployed to a deployed state without the need for intervention by the operator, i.e., "passive restraint systems" and particularly those restraint systems incorporating inflatable bags or cushions has gained general appreciation.
It is well known to protect a vehicle occupant using a cushion or bag that is inflated with gas, e.g., an "air bag" when the vehicle encounters sudden deceleration, such as in a collision. Vehicular inflatable restraint systems generally include multiple crash sensors. Such crash sensors are generally positioned about or mounted to the frame and/or body of the subject vehicle and serve to sense sudden decelerations by the vehicle. In turn, one or more of the sensors send a signal to an inflatable bag module/assembly strategically positioned within the riding compartment of the vehicle to actuate deployment of the air bag.
In such systems, the air bag is normally housed in an uninflated and folded condition to minimize space requirements. Upon actuation of the air bag system, gas is discharged from an inflator to rapidly inflate the bag. During deployment, the rapidly evolving gas with which the bag is typically filled is an inert gas, e.g., nitrogen.
In general, such systems are designed to result in inflation of the air bag in a matter of a few milliseconds and with the bag thus serving to restrain the movement of the vehicle occupant as the collision proceeds.
Inflatable restraint systems have been devised for automotive vehicles in which one or more air bags are stored in one or more storage compartments within the vehicle. In general, an air bag provided for the protection of a vehicle driver, i.e., a driver side air bag, is stored within a module including an inflator, the air bag itself, a housing, a door/cover or some form of closure panel member, and attachment means mounted in the steering wheel of the vehicle. Whereas, an air bag for the protection of a front seat passenger, i.e., a passenger side air bag, is typically stored within a module mounted in the instrument panel/dash board of the vehicle. In either case, the door/cover of such installations commonly include a face portion which, in the standard state, provides closure to the assembly. Upon activation of the system and initial bag deployment, the door/cover(s) move out of the way, e.g., "open," to form an opening through which the air bag will be deployed.
In order to improve the aesthetic appearance of the closure and to reduce the likelihood of tampering with the system, such closure panel members or doors are commonly designed so as to minimize the visual impression of the presence of the air bag and air bag deployment opening thereunder, e.g., improve fir and finish.
In general, product designs involving several interfitting pieces, each sized and shaped to particular production tolerances, are subject to tolerance stack-ups that can become significant. With respect to air bag module closures, such tolerance stack-ups can detrimentally effect the fit and finish of the vehicle interior trim. In addition, large tolerance stack-ups can result in increased part rejection and therefore in increased production cost. Thus, prior closure panel member designs have sought to reduce tolerance stack-up such as through design modifications and/or through the use of special tooling and/or processing. Such efforts, however, have tended to suffer as being too costly and/or time consuming.
Thus, a closure panel design is desired that minimizes and/or avoids tolerance stack-ups and the problems associated therewith or resulting therefrom.